I am embarrassed to say this, being as skeptical as I am of landlords, but I have never thought twice about paying a security deposit before signing the actual lease. You are on firm footing if you had to get your money back in small claims court, and unlike contractors, landlords are stuck in one place and have property that could be seized if they don't show up. If it makes you uncomfortable, you may have to work with the landlord to get a copy of the contract ahead of time. Otherwise, you could do what many other people do and trust that the landlord isn't going to screw you over.